硅基缝波导的偏振特性和非对称波导的偏振分束

发布时间：2018-03-13 19:27

  本文选题：偏振分束器　切入点：硅基光波导　出处：《中南民族大学》2015年硕士论文　论文类型：学位论文

【摘要】：偏振是光波的基本属性之一。研究不同偏振态的光波在传输过程中的性质,以及研究把不同偏振态的光波高效分离的方法,在光通信、偏振检测与分析、激光调制、偏振成像和投影系统等领域有着巨大的理论与应用价值。本文使用平面波法和有限时域差分法,针对通常研究只讨论硅纳米狭缝波导中准横磁模(TM)偏振传输的问题,较全面的研究了准TM偏振和准横电模(TE)偏振在硅纳米狭缝波导中双偏振传输的带宽以及光场分布特性;针对常规硅偏振分束器尺寸较大的问题,设计了一种基于非对称定向耦合波导的新型紧凑型偏振分束器。本文的主要工作有:(1)采用三维数值研究法,研究了硅基缝波导的偏振特性。通过调节狭缝波导中硅介质的宽度,获得了带宽达320.6 nm的双偏振单模狭缝波导;并且发现在该带宽范围内,准TE偏振的电场强度在狭缝中能够获得增强,而对准TM偏振则不具有增强作用。这为进一步设计硅基缝波导的偏振相关器件奠定了基础。(2)采用平面波法设计了一种二维非对称定向耦合波导的紧凑型偏振分束器,并使用有限时域差分法验证了偏振分束器设计的正确性。该分束器的耦合区设计长度最小为2.88μm,验证长度为2.75μm;两种方法的结果符合得很好,表明偏振分束器的设计是正确的。(3)基于上述设计的非对称偏振分束器,又研究了偏振分束器输入和输出端S型耦合弯曲波导的长度和弯曲角度,非对称定向耦合结构中条形波导和周期型波导之间的狭缝宽度对偏振分束器消光比和插入损耗的影响。二维有限时域差分法表明,当中心波长为1550 nm时,弯曲角度为16 o和狭缝宽度为99.05nm的带S型弯曲耦合输入输出段的偏振分束器,在100 nm的带宽内,TE和TM模式的消光比均大于15 dB,且插入损耗均小于0.8 dB。这为设计和制作超小型硅基偏振分束器奠定了基础。
[Abstract]:Polarization is one of the basic properties of light waves. The properties of different polarization states in the process of transmission are studied, and the methods to efficiently separate the different polarization states of light waves in optical communication, polarization detection and analysis, laser modulation are studied. Polarization imaging and projection systems have great theoretical and practical value. In this paper, the plane wave method and the finite difference time-domain method are used to study the polarization propagation of quasi-transverse magnetic mode (TMM) in silicon nanoscale slit waveguides. The bandwidth and optical field distribution of quasi-TM polarization and quasi-transverse electric mode polarization polarization in silicon nanoscale slit waveguide are studied in detail, aiming at the problem of the larger size of conventional silicon polarization splitter. A new compact polarization beam splitter based on asymmetric directional coupling waveguide is designed. The main work of this paper is to study the polarization characteristics of silicon based slit waveguide by using three-dimensional numerical method. By adjusting the width of silicon dielectric in slit waveguide, A dual-polarization single-mode slit waveguide with a bandwidth of 320.6 nm is obtained, and it is found that the electric field intensity of quasi-te polarization can be enhanced in the slit within this bandwidth range. The polarization alignment of TM has no enhancement effect, which lays a foundation for the further design of polarization-related devices for silicon-based slit waveguides. A compact polarization splitter for two-dimensional asymmetric directional coupled waveguides is designed by plane wave method. The design of the polarization beam splitter is verified by the finite difference time domain method. The minimum design length of the coupling region is 2.88 渭 m and the verification length is 2.75 渭 m. The results of the two methods are in good agreement with each other. It is shown that the design of polarization splitter is correct. (3) based on the asymmetric polarization splitter designed above, the length and bending angle of the S-type coupling curved waveguide at the input and output ends of the polarization splitter are studied. The effect of slit width between strip waveguide and periodic waveguide on extinction ratio and insertion loss of polarization splitter in asymmetric directional coupling structure. The two-dimensional finite-difference time-domain method shows that when the central wavelength is 1550 nm, A polarization beam splitter with S-type bending coupling input and output section with a bending angle of 16 o and a slit width of 99.05 nm, The extinction ratio of te and TM modes is greater than 15 dB and the insertion loss is less than 0.8 dB in 100 nm bandwidth, which lays a foundation for the design and fabrication of a miniature silicon based polarization beam splitter.
【学位授予单位】：中南民族大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN252
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本文编号：1607830